144 The Naturalist in La Plata. 



in the mud ; and this perhaps accounts for the more 

 or less aquatic habits of the jaguar, aguara-guazii, 

 the large Oervus paludosus, tapir, capybara, and 

 peccary. Monkeys, which are most abundant, are 

 a notable exception ; but these animals have the 

 habit of attending to each other's skins, and spend 

 a great deal of their time in picking off the parasites. 

 But how do birds escape the ticks, since these 

 parasites do not confine their attacks to any one 

 class of animals, but attach themselves impartially 

 to any living thing coming within reach of their 

 hooks, from snake to man ? My own observations 

 bearing on this point refer less to the Ixodes than 

 to the minute bete-rouge, which is excessively 

 abundant in the Plata district, where it is known as 

 bicho Colorado, and in size and habits resembles the 

 English Leptus autumnalis. It is so small that, 

 notwithstanding its bright scarlet colour, it can only 

 be discerned by bringing the eye close to it ; and 

 being, moreover, exceedingly active and abundant 

 in all shady places in summer — making life a misery 

 to careless human beings — it must be very much 

 more dangerous to birds than the larger sedentary 

 Ixodes. The bete-rouge invariably lodges beneath 

 the wings of birds, where the loose scanty plumage 

 affords easy access to the skin. Domestic birds 

 suffer a great deal from its persecutions, and their 

 young, if allowed to run about in shady places, die 

 of the irritation. Wild birds, however, seem to be 

 very little troubled, and most of those I have exa- 

 mined have been almost entirely free from parasites. 

 Probably they are much more sensitive than the 

 domestic birds, and able to feel and pick off the 



